Train-control system



10, 1931. w so v 1,791,779

I TRAIN CONTROL SYSTEI v Origina]. Filed April 18, 1922 2 Sheets-Sheet 11931. A. G. WILLIAMSON 1,791,779

TRAIN CONTROL SYSTEM Original Filed April/ 1922 2 Sheets-Sheet 2 Fig.5-

Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE.

ABBA G. WILLIAMSON, OF CARNEGIE, PENNSYLVANIA, ASSIGNOB, BY MEBNEASSIGN- .MENTS, TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE,FENNSYL- yams, A conronarron or PENNSYLVANIA.

mam-common stem Application filed April 18, 1822, Serial Io. 555,804.Renewed November 18, 1928.

This invention relates to traflic controlling systems such as are usedin connection with trains, the traflic controlling means being eithermerely signals or retarding or stopping sponse to traflic conditions, sothat whenever traflic conditions of the track change the control of thetrain will likewise change, and to do this in such a manner that morethan two operating conditions can be imposed on the train. That isinstead of .merely, say, proceed "and danger indications, there anddanger indications, given. Also that this shall preferably beaccompllshed without the use of ram s or contact members along therunning ralls.

One feature of the invention centers around two pick-up circuits,carried by the train, of different characteristics-one I will call anindirect and the other I will call a direct pick-up circuit. Preferablythe indirect pick-up circuit is of the induced current type andpreferably the direct pick-up circuit is of the electrostatic type. Thetwo pick-up circuits are responsive to different traflic conditions, andpreferably'impose different controlling conditions on the train. So faras certain features of the invention are concerned the two pick-upcircuits may each include either one or more controlling elements suchas amplifiers or rectifiers, but preferably rectifiers of the charactershown in Patent No. 1,695,131 of December 11, 1928, are employed.Prefers electrically, and electron tubes controlled .magnetically andusually known as magcuits control the grid potential to render itnegative by means of a condenser or otherwise under certain operat ngcond1t1ons, and this may change the resistance of a tram con trollingcircuit to a new maintained value I so long .as certain traflicconditions prevail, or as shown in application Ser. No. 372,567 filedJune 21, 1929, the effect of impressing symmetrical ulsations upon thecontrolling element may to produce a non-symmetrical resistance in thetrain controlling circuit and thereby efl'ect train control.

In connection with the above train equipment certain track equipment isused which may, however, vary widely. The rails may for instance haveimpressed ;upon them a pulsatin current, and by pulsating I mean toinclu e both an alternating or an oscillatshall be at least, say,.proceed, caut1on.-f

ing current or an interrupted or fluctuating direct current, or whenmagnetrons are used as controlling elements, a simple uninterrupteddirect current may be employed. The

"track current for influencing the indirect of application Ser. N 0.549,663 filed April 5 1922. However, the combination of trackway meansto supply interrupted or periodically varying current in combinationwith cab equipment controlled by the influence of such current is notclaimed herein but forms the subject matter of applicants co-pendingapplication Ser. No. 215,318 filed August 25,

ably also the controlling element will be i 21927.

the form of electron tubes, and byelectron tubes I mean both electrontubes, controlled Otherfeatures of invention will appear as thespecification proceeds. I In the accompanying drawings the invention isshown in a concrete and preferred form in which Fig. 1 is a diagrammaticview of one form of track circuits that may tion with the invention.

Fig. 2 is a diagrammatic view of a preferred form of train carriedcircuits embodying the invention. Y 1

Fig. 3 is a side elevation, partly broken be used in connecaway, of arelay that may be used in the train controlling circuit.

Fig. 4 is a to plan view of same. A

Fig. 5 is a ottom plan view of the ele ments of the relay with theneutral armatures omitted.

Fig. 6 is a sectional dletail view of a release valve that may be usedinconnection with my invention.

Referring to Fig. 1, 1 and 2 represent the rails of a traffic trackdivided into blocks, W, X, Y and Z in a manner well understood as bymeans of insulation 3. 4 and 5 indicate line wires fed by the singlefrequency generator G. Associated with each block is a main transformerindicated by Tw, T411, and Ty and the secondary 6 of each of thosetransformers is connected by means of conductors 7 and 9 with primary 8of a track transformer indicated variously as N'w, Na; and Ny. Secondary13 of the track transformer is connected by means of leads 16 and 17with rails 1 and 2 thereby supplying current to both of said rails of agiven block. These elements together with a relay such as m, 711 or reconstitute the ordinary track circuit. Connected in parallel with thetrack transformer is a subsidiary transformer indicated at Mac, Mac andMy, the primary 11 of which is connected by wires 10 and 12 withconductors 7 and 9, and this subsidiary transformer applies a voltage toacircuit connected to one rail and ground, which circuit is as followsConnected with one side of secondary 18 is a conductor 19, which isgrounded, and connected with the other side of secondary 18 is aconductor indicated by wires 20, 23 and 25, the latter connected to lead16. 15 and 24 indicate impedances, one for the track circuit and theother for the rail and ground circuit. 21, with an exponent indicatinits block location, is a cir cuit breaker interposed in the rail andground circuit and this circuit breaker is actuated either by signal Sof the block in advance or by relay 7' likewise of the block in advance.

Normall current will flow in the rails of the track circuit fed by tracktransformer N and a voltage will be applied by secondary 18 along wire'20, circuit breaker 21, wire 23, impedance 24, and wires 25 and 16 torail 1. The other side of secondary 18 being connected to ground by wire19, a difference of potential is created between rail and ground (zeroearth potential). It will be under-- stood that rail 1 is not groundedand that it does not have the same potential (zero) as the earth becauseit is insulated to a certain extent by the ballast. When, therefore, atrain as enters a block under normal conditions, the indirect and directpick-up circuits carried by the train will both be influenced. Theeffect of the presence of a train as at K in block Z on the block inrear Y will be readily understood. Such train will short circuit thetrack circuit thereby actuating signal S2 or deenergizin relay 72 andwill thereby move circuit brea er 217 against stop 22y thereby rupturingthe rail and ground circuit of. block Y and a train in block Y wouldtherefore not have its direct pick-up circuit influenced, but wouldnevertheless have its indirect pick-up circuit influenced because thetrack circuit of block Y is not affected by the presence of a train inblock Z. Should a second train advance from block Y into the occupiedblock Z it is clear that such second train would not have either itsindirect or its direct pick-up circuits influenced. Referring nowgenerally to Fig. 2 the exemplification' of train equipment there shownfor use in connection with my invention 'is as follows:

The controlling elements of the two pickup circuits are here shown astwo electrically controlled electron tubes E and E. notes a cabindicator having differently colored lights for different traflicconditions. R and R indicate two polarized relays controlled by thepick-up circuits and controlling the mdicator lights. D is a dynamotorwhich receives say thirty-two volts in its infeed circuit over wires 51and 52 conveniently leading from the headlight generator, that is,current flows from the headlight generator, along wire 52, through themotor end of dynamotor D and from the latter by way of brush 37 to wire51 and thence to headlight generator. Dynamotor D supplies from itsgenerator end say' 350 volts to the plate-filament circuits, saidcircuits to be pointed out later; and by means of third brush 27,properly positioned on the commutator of the motor end of D, about eightvolts are supplied to the filament circuits of the electron tubes, saidcircuits also to be pointed out later. The indicator lights are feddirectly from wires 51 and 52. The trainequipment may further consist ofbrake controlling means consisting here generally of magnet valve M,brake valve B and release valve R1). As here shown, the construction ofthese parts is as follows:

When magnet M' is energized, valve 127 is in its closed position and.valve 128 is in its open position thereby permitting pressure to flowfrom the brake pipe, past valve 128 and through port 129 into pistonchamber 130 of brake valve B. This pressure will force piston 131 to theright in Fig. 2, thereby closing valve 133 which stops the flow ofpressure from the brake pipe to exhaust pipe 134 and port 135- ofrelease valve Re. When magnet valve M is deenergized, air pressure andspring 129 seat Valve 128 and open valve 127 thereby stopping the flowof pressure from the brake pipe to port 129. The pressure accumulated inchamber 130 will now be exhausted through port 129, past valve 127 and I.de-.

out through port 136, the action of spring 132 moving piston 131 to theleft in Fig. 2. By this action valve 133 is opened so as to permit freeflow from the brake pipe to exhaust pipe 134 and release valve port 135.If desired, release. valve Re can be so arranged that it is accessibleto the engineer and, if such be the case, he can then turn release valveinto the position shown in Fig. 6, thereby stopping application of thebrakes. The engineer may then proceed under the caution visual signal tobe described later. When magnet M is again energized, piston 131 willagain be moved to the right in Fig. 2 and member 137, movable with saidpiston, will then automatically force handle 138 and thereby releasevalve R'v into the position shown. in Fig. 2, so that when the magnet isagain deenergized the brakes will be applied.

Polarizedrelays R and B may be alike and are of the polarizeddirect-current type. The description of one of these relays will sufficefor both. 1

Referring to Figs. 3, 4 and 5, the coils 90 and 91 of the relays are onspools which slip over cores 92 and 93, said cores having pole pieces 94and 95 magnetically connected at the top by soft iron piece 96. Neutralarmature 55 (in the case of relay R) is pivoted at 55a and is attractedto the poles whenever suflicient current flows in the coils. A permanentmagnet 97 fits at its top into soft iron piece 96 and carries at itsbottom soft iron piece 98 to which latter is pivoted at 5811, so as toswing freely, a polarized armature 58 (in the case of relay R). Assumingthat the top of permanent magnet 97 ispositive and that its bottom endis negative, then both poles 94 and 95 will be positive and both-ends ofpolarized armature 58 will be negative, and, as the air gap between 58and 94 is greater than the air gap between 58 and 95, armature 58 willswing into the position indicated in F ig. 5 against contact 72 (in thecase of relay R)-When no current flows in the coils. Now. if a currentof proper value so flows in coils 90 and 91 as .out later.

to render pole piece 94 positive and pole piece 95 negative, thenarmature 58 will be attracted by pole piece 94 and will swing intoengagement with contact 59 (in the case of.relay R) If, however, currentof greater strength than previously assumed is caused to flow throughcoils 90 and 91 then, due to the electro-magnetic action, asdistinguished from the polar action in the coils, and to the differencein the air gap before mentioned, armature 58 will swing into itsoriginal position as shown in Fig. 5. Thus the armature will occupy thesame position when no current is present 1n coils 90 and 91 as it doeswhen a strong current energizes said coils, and will occupy anotherposition when a weak current energizes said coils. The object of thiswill be pointed The specific form here shown (Fig. 2 of train carriedcircuits will now be descri ed. The indirect pick-up circuit, in thiscase an induced-current circuit, of electron tube E is as follows: coil28,-energized by the current impressed between the two rails of thetrack,

conductor 29, condenser 30, grid 31 of electron tube E, filament 32 ofelectron tube E, conductor 34 back tocoil 28. 35 is a tuning condenserto tune the circuit to the proper frequency of the track circuit. Thedirect pickup circuit of electron tube E is as follows: grid 84 of tubeE, filament 38 of tube E,

wire 82, condenser 81 and wire back to to brush 37; The plate circuitsof the tWotubes are likewise connected in parallel and are as follows:from brush 43, by wire 44, re-

lay R, wire 45, plate 42 of tube E, filament 32 of tube E, wire 33, wire46 and back to brush 47; and from brush 43, by wire 49, to relay R, bywire 50, to plate 48 of tube E, filament 38 of tube E, wire 40, wire 51,wire 46 back to brush 47. The proceed cab indicator light circuit is as.follows, all of the lights receiving cnrrent from the thirty-two voltsupply coming from the head light generator. Starting from wire 52,along wire 54, neutral armature 55, contact 56, wire 57, polarizedarmature 58, contact 59, wire 60, neutral armature 61, contact 62, wire63, polarlzed armature 64, contact 65, wire 66, proceed light 53 andcommon return wire 67 back to wire 51. Under caution conditions, that iswith the rail circuit between rail and ground ruptured,-the circuit willbe as fol-. lows: over the same circuit as previously described inconnection with the proceed light up to polarized armature 64 of relayR, then to contact 69, wire 7 O, to caution light 68 and then to commonreturn wire 67. The danger indicator light receives current underseveral conditions as follows: When polarized armature 58 is in itsleft-hand position against contact 72, then by way of wire 73 to danger8 ground. The filaments ofagainst contact 76, then by wires 77 and 73 Ato danger light 71 and thence to common re-. turn wire. In the form ofthe invention here up circuit.

shown, magnet M is in parallel with the roceed cab light by reason ofwire 78 lea ing from wire 66 to magnet M and thence by wire 7 9 tocommon return wire 67.

The inductive pick-up circuit controls the plate circuit of tube E inthe following manner: Plate 42 is positive, grid 31 is of the samepotential as filament 32 and the filament is heated. Thus when nocurrent flows in the induced pick-up circuit a current in one directionwill flow in the plate circ lit and through relay R, and this currentwill be the full value of current supplied by the dynamotor. We willassume this value to be 1.0. When current flows in that rail circuitwhich includes the two running rails, an alternating current will beinduced in the inductive pick- When the alternating voltage thusproduced is applied between the grid and filament, the alternatingcurrent is rectified into a direct current, current flowing only whenthe induced voltage makes the grid positive. In other words, the spacebet-ween the grid and the filament constitutes a rectifier, one of theswings of the alternating current being suppressed. If condenser 30 werewhat is generally called a leaky condenser. that is, provided with aresistance, it would be charged when the rectified current is flowingand discharge during the suppression of the swing of the current in theother direction and the result would be to render the grid potentialalternately positive and negative thus producing a current in the platecircuit having a rise and fall. Condenser 30, however, is not a leakycondenser, that is, it will not discharge, during the suppressed swing,the charge built up during the effective swing of the current. Theresult is, therefore, that a charge is gradually built up on thecondenser thereby rendering the grid negative with respect to thefilament by an amount equal to the alternating voltage induced in coil28, and the grid is maintained negative so long as current flows. Ifcurrent ceases to flow in coil 28, the condenser will graduallydischarge.

The effect of rendering and maintaining the grid negative during theflow of current in the pick-up circuit is to choke down the value of thecurrent in the plate circuit. It virtually increases the resistance ofthe plate circuit to a new maintained value. The original value of the,current in the plate circuit we assumed to be 1.0, and we will assumethat 0.4 represents the value of the choked-down current.

The effect of the grid circuit of tube E upon the plate circuit of saidtube is substantially the same as that described in connec-' tion withthe plate circuit of tube E although the action is somewhat different.By means of direct current generator D, there is estab-. lished betweenfilament 38 and plate 48 a steady difference of potential under theinfluence of which a steady current flows through the tube from 48 to38. This current thus establishes a definite potential between grid 84and filament 38 which is, however, considerably less than the differencein potential between the plate and filament. This potential we may callthe free grid potentiaL' By connecting the grid circuit directly throughwire 83 wit-h the wheels and track, the potential of the grid withrespect to ground is caused to alternate by an amount corresponding tothe voltage impressed be- ,tween rail and ground. As there is nothing tocause a corresponding variation in the potential of the filamentrelative to ground, nor in the plate with respect to the filament, acharge is gradually built up in the grid circuit by the variation inpotential of the grid with respect to the free grid potential. It mustbe understood that the ground serves, in this direct pick-up circuit, asone plate of a coupling condenser operative between the cab and trackcircuits and, following the customary usage, the potential of the groundwill be taken as the zero of potential with respect to all the others inthe system. In this case likewise the grid is rendered negative and theplate circuit current is choked down just as in tube E; and thisnotwith-- standing the change in the free grid potential due to thereduction of the plate-circuit current. As in the case of tube E, let usassume that the full value of the plate circuit current is 1.0. Thisvalue is maintained when the grid is connected to the rail and novoltage is impressed between rail and ground; and. under theseconditions, the tube is quickly brought to an equilibrium, the potentialof the filament with respect to grid and ground being approximatelyequal to the free grid potential. When now an alternating voltage isapplied between rail and ground, the potential of the grid alternateswith respect to its original value, condenser 81 is quickly charged, andthe mean potential of the grid relative to the free grid potential (andhence to the filament potential) is lowered. The plate circuit currentis therefore choked down to a value of, say, 0.4. Condenser 81 is not aleaky condenser in that it does not discharge during a swing in onedirection an amount equal to the charge accumulated during the swing inthe other direction. However, when the alternations cease in the trackcircuit between rail and ground, the condenser gradually discharges andthe free grid potential is restored. It is not absolutely necessary tohave a condenser like 81 in the grid cir- 0.8 is flowing.

train is traveling through a block which is not occupied by anothertrain and no train is in the block in advance, voltage will be appliedin the rail circuitsbetween thetwo rails and also between one rail andground. Consequently the value of the plate-circuit current of the twoelectron tubes is reduced to 0.4 and relays R and R will therefore holdarmatures 58 andfi i in the position shown in Fig. 2 thereby showing aproceed indication at 53 in the cab and holding magnet M energized.Should, however, a train be present in the block in advance then novoltage will be applied between real and ground and consequently thelate-circuit current of tube E will not be c okeddown but .will be ofthe value of 1.0. The effect of this is to cause relay R to fliparmature 64to the left thereby destroying the circuit throu h. proceedlight 53 and magnet M and establis ing a circuit through caution light68. The

brakes will therefore be applied unless the engineer moves release valveR'v' to position Fig. 6 in whichcase he should proceed with caution. Ifthe trainnow enters a block already occupied by another train, then thelit cation. 1

induced-current pick-up circuit will not be energized and consequentlythe value of the plate-circuit current of tube E will berestored to 1.0and relay R will fli armature 58 into left hand position there ydestroying the circuit through caution light 68 and The efiect ofbreaking a wire in the plate-circuits will be to deenergize relay-R or Ras the case may be which, as I have. shown, has the same effect uponarmature's 58 and 64 as when said relays were fully energized; that is,the train would get a dangerindi- It will be obvious from the foregoingthat whenever there is any change in traffic con.-

ditions suchchange will immediately be re-' flected in operatingconditions imposed upon rails, a circuit including both rails, a sec-,ond circuitincluding rail and ground,'a car, an indirect pick-upcircuit, on the car, under the control ofthe first circuit, and a directpick-up circuit also on the car and controlled by the second circuit. vi

2; A train-control system including: traific rails, a circuit includingboth rails, a second circuit includlng rail-and ground, a car, anindirect plck-up circult, on the car, under the control of the firstcircuit, a direct-pick up circuit also in the car and controlled by thesecond circuit, and trafiic controlling means, on the car, under twopick-up circuits. I

3.-- A train control system including: trafiic rails divided intoblocks," a circuit including both rails of a block, a second circuitIlIlCllld-r ing rail and said circuits eing controlled continuously bytraflic conditions of another block, a car, an indirect pick-up circuit,on the'car, conthe control of the 1 ound in each block, one of trolledby the first circuit, anda direct pick-Q up circuit also on the car andinfluenced by 1 the second circuit.

4; A traincontrol system ing-rail and ground in-each block andcontinuousl controlled. by trafiic conditions of another lock, a car, anindirect pick-up circuit, .on theicar, controlled by the first circuit,and ai'direct pick-up circuit also on the 7 car and influenced by thesecond circuit.

5. -A' train control system including: trafi v i fic rails divided intoblocks, a circuit including both rails of. a block, a second circuitincluding: traflic rails divided into blocks, a circuit includin bothrails of ablock, a second circuit inclu includm rail and ground in eachblock, one

of said clrcuits being controlled continuously by traflic conditions ofanother block, a car, an indirect pick-up circuit, on the car, controlled by the first circuit, a direct pick-up circuit also on the carand influenced by the second circuit, and traflic controlling means onthe car under the control of the two pick-' upcircuits. r I f 6. A traincontrol stem including: traffic rails divided into If? ingboth rails ofa block, a second circuit in-' I ocks, a clrcult includeluding rail andground in each block and I continuously controlled by trafiilc"conditions of another block, a car, an indirect. ick-up circuit, on thecar, controlled by the rst circuit, a-v direct and influence by thesecond circuit, and trafiic controlling means on the car under thecontrol of the two pick-up circuits. -7. Atrain control systemincluding: traflic rails divided into blocks, a circuit including] both,railsin series, 'a second circuit, connected to ground at one side andto at least one of the rails at its other side, for main taining'voltage above ground potential on at i i least one of said rails, a car,an indirect pick- 1. A tram control system includlngz traific' pick-upcircuit also on the car up circuit, on the car, under the control of ficrails divided intoblocks', a circuit 1ncl ud-,

ing both rails in series, a second circuit, connee-ted to ground at oneside and to at least one of the rails at its other side, for mainndcircuit, and trafiic controlling means, on

the car, under the control of the two pick-up circuits.

9. A train control system including: traftic rails divided into blocks,a circuit includmg both rails in series, a second circuit, con-.

nected to ground at one side andto at least one of the rails at itsother side, for maintaining voltage above ground potential on at leastone of said rails, one of said circuits be- "cuit.

ing controlled continuously by traflic conditlons of another block, acar, an indirect pickup clrcult, on the car, under the control of thefirst. circuit, and a direct pick-up circuit also on the car andcontrolled by the second cir- 10. A train control system includingtraffic rails divided into blocks, a circuit includmg both rails inseries, a second circuit, connected to ground at one side and to atleast one of the rails at its other side, for maintaining voltage aboveground potential on at least one of said rails, and continuously controlled by trafiic conditions of another block, a car, an indirectpick-up circuit, on the car, under the control of the first circuit, anda direct pick-up circuit also on the car 'and controlled by the secondcircuit.

11. A train control system including: traffic rails divided into blocks,a circuit including both rails in series, a second circuit, connected toground atone side and to at least one of the rails at its other side,for maintaining voltage above ground potential on at least one of saidrails, one of said circuits being controlled continuously by trafficconditions of another block, a car, an indirect pickup circuit, on thecar, under the control of the first circuit, a direct pick-up circuitalso on the car and controlled by the second circuit, and trafiiccontrolling means, on the car, under the control of the two pick-upcircuits.

12. A train control system including: traffic rails divided into blocks,a circuit including both rails in series, a second circuit, connected toground at one side and to at least one of the rails at its other side,for maintaining voltage above ground potential on at least one of saidrails, and continuously controlled by trafiic conditions of anotherblock, a car, an indirect pick-up circuit, on the car, under the controlof the first circuit, a

direct pick-up circuit also on the car and controlled by thesecondcircuit, and traflic controlling means, on the car, under thecontrol of the two pick-up circuits.

13. A train control system including: a

trafiic track, divided into blocks, a track cir-- cuit connected toground on one side and to at least one traflic rail on the other side tomaintain a difference of potential between rail and ground, a car, and apick-up circuit on the car electrostatically coupled to the trackcircuit.

14. A train control system including: a trafiic track, divided intoblocks, a track circuit connected to ground on one side and to at leastone trafiic rail on the other side to maintain a difference of potentialbetween rail and ground, a car, a plck-up circuit on the carelectrostatically coupled to the track circuit, and trafiic controllingmeans on the car under the control of the pick-up circuit.

15. A train control system including: a trafiic track divided intoblocks, a track circuit connected to ground on one side and to at leastone trafiic rail on the other side to maintain a difierence of potentialbetween rail and. ground, a car, a pick-upcircuit on the carelectrostatically coupled to the track circuit, and means forcontrolling the track circuit in response to traflic conditions ofanother block.

- 16. A train control system including: a traific track divided intoblocks, a track cir-" cuit connected to ground on one side and to atleast one traflic rail on the other side to maintain a difference ofpotential between rail and ground, a car, a pick-up circuit on the carelectrostatically coupled to the track circuit, traffic controllingmeans on the car under the control of the pick-up circuit, and means forcontrolling the track circuit in response to traflic conditions ofanother block.

17. A train control system including: a traflic track, a track circuitconnected to ground on one side and to at least one trafiic rail on theother side, and a pick-up circu1t on the car so coupled to the trackcircuit that the ground serves as one plate of a coupling condenser.

18. A train control system including: a traffic track, a track circuitconnected to ground on one side and to at least one trafiic rail on theother side, a pick-up circuit on the car so coupled to the track circuitthat the ground serves as one plate of a coupling condenser, and trafiiccontrolling means on the car under the control of the pick-up circuit.

19. A train control system including: a trafiic track, a track circuitconnected to ground on one side and to at least one trafiic rail on theother side, a pick-up circuit on the car so coupled to the track circuitthat the ground serves as one plate of a coupling condenser, and meansfor controlling the track circuit in response to traflic conditions ofanother block.

20. A train control system including: a traflic track, a track circuitconnected to ground on one sideand to at least one traffic rail on theother side, a pick-up circuit on the car so coupled to the track circuitthat the' ground serves as one plate of a coupling coni denser, trafliccontrolling means on the car under the control of the nick-up circuit,and means for controlling the track circuit in response to trafficconditions of another block.

21. A train control system including: traffic rails, a circuit includingboth rails, a second circuit including rail and ground, af

car, an indirect pick-up circuit, onthe car, under the control of thefirst c rcuit, a direct pick-up circuit also in the car and controlled"circuit including rail and ground, a car, an

indirect pick-up circuit, on the car, under the control of the firstcircuit, a direct pick-up circuit also on the car and controlled by thesecond circuit, and two rectifiers, one under the control of one and theother under the control of the other pick-up circuit.

23. A train control system including: traffic rails, a circuit includingboth rails, a second circuit including rail and ground, a car, anindirect pick-up circuit, on the car, under the control of the firstcircuit, a direct pick-up circuit also on the car and controlled by thesecond circuit, and two electron tubes, the potential of the grid of onetubecontrollod by one pick-up circuit and thepotential of the grid ofthe other tube controlled by the other pick-up circuit. i

24. A train control system including: traflic rails, a circuit includingboth rails, a second cir:-uit including rail and ground, a car, aninduccd-current pick-up circuit, on the car, energized by the firstcircuit and a direct pick-up ircuit also on the car and influenced bythe second circuit.

25. A train control system including: traffic rails divided into blocks,a circuit including both rails. of a block, a second circuit includingrail and ground in each block, one of said circuits being controlled bytraffic conditions of another block, a car, an induced-current pick-upcircuit, on the car, energized by the first circuit, and a directpick-up circuit also on the car and. influenced by the second circuit.

26. A train control system including: traflic rails divided into blocks,a circuit including" both rails of a block, a second circuit includingrail and ground in each block and controlled by traflic conditions ofanother block, a car, an induced-cm'rcnt pick-up circuit, on the car,energized by the first circuit, and a direct pick-up circuit also on thecar and influenced by the second circuit.

27. A train control system including: traflitrrails divided into blocks,a circuit including both rails of a block. a second circuit includingrail and ground in each block, one of said circuitsv eing controlledcontinuously by traflic conditions of another block, a car,

an induced-current ick-up circuit, on the car, energized by the rstcircuit, and a direct pick-up circuit also on the car and influenced bythe second circuit.

28. A train control system including: traflic rails divided into blocks,a circuit including both rails of a block, a second circuit includ ingrail and ground ineach block and con-- trolled continuously by trafficconditions of another? 1block,a" car, "an; induced-current- ;pick-upcircuit, 011 the car, energized by the first "circuit, and a directpick-up circuit also on the car and'influenced-by' the second circuit.

29. A train control system including: traflic' rails, a circuitincluding both rails, a second c rcuit lncludlng rail and ground, a car,an induced-current pick-up clrcuit, on the car,

energized by the first circuit, a direct pick upclrcuit also on the carand influenced by the second circuit, and two'elect'ron tubes,

one under the control of one and the'otherl under the control of theother pick-up cir I 30. A train control system including: traflic rails,a circuit including both rails, a second circuit including rail andground, a car, an induced-current pick-up circuit, on the car, energizedby the first circuit, a direct pick-up circuit also on the car andinfluenced by the second circuit, and tWo rectifiers, one under thecontrol of one and the other under the control of the other pick-upcircuit.

31. A train control system including: traffic rails, a circuit includingboth rails, a second circuit including rail and ground, a car, aninduced-current pick-up circuit, on the car, energized by the 'firstcircuit, a direct pickup circuit also on the car and influenced by thesecond circuit, and two electron tubes, the potential of the grid of onetube controlled by one .pick-up circuit and the potential of the grid ofthe other tube controlled by the other pick-up circuit.

32. A train control system including: traflic rails divided into blocks,a circuit including both rails of a block, a second circuit includingrail and ground in each block, one of said circuits being controlled bytraffic con,- ditions. of another block, a car, an inducedcurrentpick-up circuit, on the car, energized by the first circuit, a directpick-up circuit also on the car and influenced by the second circuit,and two electron tubes, one under the control of one and the other underthe control of the other pick-up circuit.

33. A train control system including trafflc rails divided into blocks,a circuit including both rails of a block, a second circuit includingrail and ground in each block, one of said circuits being controlled bytrafiic conditions of another block, a car, an induced-current pick-upcircuit, on the car, energized by the first circuit, a direct pick-upcircuit also on the car and influenced by the second circuit, and twor'ectifiers, one under 1 the control of one and the other under thecontrol of the other pick-up circuit.

34. A train control system including trafiic 5 rails divided intoblocks, a ,circuit including both rails of a block, asecond circuitincluding rail and ground in each block, one of said circuits beingcontrol-led by traffic conditions of another block, a car, aninduced-current pick-up circuit, on the car, energized by thefirstacircuit, a direct pick-up circuit also on the car and influencedby the second circuit, and two electron tubes, the potential of the gridof one tube controlled by one pick-up circuit and the potential of: thegrid of the other tube controlled by the other pick-up circuit. 1 Y

35. A car carried train control system including: two electron tubes, 11source of .power, two plate circuits arranged in parallel, each circuitincluding the plate and filament of a tube, fed by said sourceof power,two filament circuits, one for each tube, also arranged in parallel andfed by said source of power, two independently controlled relays, oneincluded in each plate circuit, and a traffic controlling circuit underthe control of both relays. w y

36. A car carried train controlsystem including: two electron tubes, asource of power, two plate circuits arranged in parallel, each circuitincluding the plate and filament of a tube, fed by said source of power,two filament circu1ts','one for each tube, also arranged in parallel andfed by said source of power, two independently controlled relays, oneincluded in each plate circuit, a trafiic controlling circuit under thecontrol of both relays, and feed wires con- 40 nected to said trafliccontrolling circuit and connected to the source of power.

. 37. A car carried train control system ineluding; two electron tubes,a source of power, two plate circuits arranged in parallel, each circuitincluding the plate and filament of a tube, fed by said source of power,two filament circuits, one for each tube, also arranged in parallel andfed by said source of power, two independently controlledrelays, oneincluded in each plate circuit, a traffic controlling circuit under thecontrol. of both relays, and independent pick-up circuits forcontrolling the grid of each tube.

38. A car carried train'control system in- '55 eluding: two electrontubes, 2. source of power, two plate circuits arranged in parallel,,eachcircuit including the plate and filament of a tube, fed by said sourceof power, two filament circuits, one for each tube, also arranged inparallel and fed by said source of power, two independently controlledrelays, one included in each plate circuit, a traflic controllingcircuit under the control of both relays, feed wires connected to .65said trafiic controlling circuit and connected to the source of power,and independent pick up circuits for controlling the grid of each tube.

39. A car carried train control system ineluding? two electron tubes, asource of power, two plate circuits arranged in parallel, each circuitincluding the plate and filament of a tube, fed by said source of power,two filament circuits, one for eachtube, also arranged in parallel andfed by said source of power, two in de endently controlled relays, oneincluded in each plate circuit, a

traflic controlling circuit under the control of both relays, aninduced-current pick-up circuit controlling the grid of one tube, and adirect pick-up circuit controlling the grid of theother tube.

40. A car carried train control system including: two electron tubes, asource of power, two plate circuits arranged in parallel, each circuitincluding the plate and filament of a tube, fed by said source of power,two filament circuits, one for each tube, also arranged in parallel andfed by said source ofpower, two independently controlled relays, one'included m each late circuit, a traflic controlling circuit un er thecontrol of both relays, feed wires connected to said traflic controllingcircuit and connected to the source of power, an induced-current ick-upcircuit controlling the grid of one to e, and a direct pick-up circuitcontrolling the grid of the other tube.

41., A train control system including: a trafiic track arranged inblocks, two traincontrolling track circuits for each block each of whichincludes the traflic. track, a train, two train-carried'charged circuitseach having a normal flow of current of a given value, train-carriedpick-up and controlling apparatus to lessen the value of the current in.oneor both of the charged circuits in response to certain trafiicconditions of the track circuits, a circuit closing means under thecontrol of the charged circuits, and train-carried signal- I ingcircuits selectively controlled by the said circuit closing means.

'42. A train control system including: a

ing circuit held closed by said circuit closing means as long as thecurrent in the one charged circuit is maintained at the lesser filament,a

value by the said trafiic condition of the trackway means.

43. A car carried train control system including: an electron tube havinaplate, grid and filament with circuits there or, means for renderingthe grid negative in potential with respect to the filament to controlthe flow of current in the plate circuit, an electromagnet controlled bythe plate circuit, a permanent magnet, and a car-governing armaturecontrolled jointly by said electro-magnet and said permanent magnet andarranged to assume one given posltion when the plate circuit iscontrolled by the negative potential on the grid, and to assume anothergiven position when the plate circuit is not controlled by negativepotential on the grid or when the permanent magnet only is active.

44. A car carried train control system including: an electron tubehaving a plate, grid and filament with circuits therefor, means forrendering the grid negative in potential with respect to the filament tocontrol the flow of current in the plate circuit, an electro-magnetcontrolled by the plate circuit, a permanent magnet, and a car-governingarmature controlled jointly by said electro-magnet and said permanentmagnet and arranged to assume one given condition when the plate circuitis controlled by the negative potential on the grid, and to assumeanother given condition when the plate circuit is not controlled by anegative potential of the grid or when the permanent magnet only isactive.

45. A car carried train control system including: an electron tubehaving a late, a iglfid and a filament, a circuit for heating saidament, a receiving circuit for controlling the potential of the gridwith respect to the late circuit having a current source capab e ofsupplying a direct current flow of a given value in response to a givenpotential of the grid with respect to the filament, a direct currentpolarized car governing armature, meansunder the control of the platecircuit to cause said armature to assume one position in response to theestablishing of the current flo'w of said given value, and to cause saidarmature to assume a second position in response both to an increase ora decrease in the value of the direct current flowin in the platecircuit with respect to said given value; and means for influencing,under certain conditions, said receiving circuit to create said givenpotential of the grid with respect to the filament.

46. A car carried train control system including: a car carriedreceiving circuit, a car carried closed circuit having a source ofdirect current of a given polarity, a car carried translating meansresponsive to an alternating current induced in the receiving circult toestablish a given value of the direct current flowing in the closedcircuit but not affecting the polarity'or continuity of said circuit, adirect current polarized car governing armature, means under the controlof the closed circuit to cause said armature to assume one position inresponse to the establishing of said given value of current in theclosed circuit, and to cause said armature to assume a second positionin response both to an increase or a. decrease in the value of thedirect current flowing in the closed circuit with respect to said givenvalue, and a trackway sourceof alternating current to induce, undercertain conditions, an alternating current in the receiving circuit;

47. A train control system includin a train-carried electron tube havinga p ate, a grid,.and a filament with circuits therefor, trackway meansto exert an influence, under clear traflic conditions, that determinesthe potential of the grid with respect to the filament to therebycontrol the flow of current in the plate circuit, an electro-magnetenergized by the flow of current in the plate circuit, a permanentmagnet, and a trailic-governing polarized armature, controlled jointlyby the influence of the electro-magnet and the permanent magnet, whichassumes a clear traffic-governing condition in response to theenergization of the electro-magnet that *of current, a trackway means toexert an influence, under certain trafiic conditions, to control theflow of current in the closed circuit, an electro-magnet energized bythe flow of current in the closed circuit, a perma-' nent magnet, and atrafiic-governing olar ized armature, controlled jointly by t einfluence of the electro-magnet and the permanent magnet, which assumesone traflicgoverning condition in response to the enerization of theelectro-magnet that results rom the influence of the trackway means, andwhich assumes a second traflic overning condition in response to theenerglzation of the electro-magnet that 'resultsfrom the absence of theinfluence of the trackway means, or when the permanent magnet only isactive in the control of said armature.

Signed at Pittsburgh, in the county of Allegheny and State ofPennsylvania, this 6th day of April, 1922.

ARBA G. WILLIAMSON.

